Able strokes gas panel display having monogram type characters with matrix address

ABSTRACT

A high resolution gaseous discharge display comprises an encapsulated panel array of bistable charge storage areas defining linearly shaped discharge cells or sites, each cell being defined by a pair of congruent linear portions formed by generally orthogonally arranged conductors insulated from direct contact with the gas by a dielectric, which, when properly energized, produce a confined gaseous discharge in the selected cell. The cells are arranged in character font areas in columns and rows at the intersections of groups of the conductor lines, the conductors being configured at the character positions to define linear cells constituting character font strokes or elements.

Milled States Patent 1 lsippenlian Sept. 13, 1973 B. William Kippenhan,Hyde Park, NY.

International Business Machines Corporation, Armonk, NY.

Filed: Sept, 29, 1971 Appl. No.: 184,743

Inventor:

Assignee:

References Cited UNITED STATES PATENTS 10/1971 Coleman et a1. 340/324 M5/1972 Schmersal et al 340/324 M 3,190,957 6/1965 Foley et ah. 178/30Primary Examiner-John W. Caldwell Assistant Examiner-Marshall M. CurtisAttorney-Frederick D. Poag et al.

[57] ABSTRACT A high resolution gaseous discharge display comprises anencapsulated panel array of bistable charge storage areas defininglinearly shaped discharge cells or sites, each cell being defined by apair of congruent linear portions formed by generally orthogonallyarranged conductors insulated from direct contact with the gas by adielectric, which, when properly energized, produce a confined gaseousdischarge in the selected cell. The cells are arranged in character fontareas in columns and rows at the intersections of groups of theconductor lines, the conductors being configured at the characterpositions to define linear cells constituting character font strokes orelements.

11 Claims, 7 Drawing Figures emos BACKGROUND OF THE INVENTION Thisinvention relates to display matrices and more particularly to a plasmaor gaseous discharge display characterized by matrix grids of suchconfiguration as to yield linear areas of congruence at cross-overregions of the respective arrays of the matrix, so as to yield characterstroke or font elements which are each addressable by a pair ofconductors.

In the prior art of gas panel displays, the display may be generated asa multiplicity of individual points corresponding to the cross-overareas of individual straight line conductors of a coordinate pair in thetwo arrays. While a display of this kind has great flexibility, a greatmany separately addressable conductors are needed to provide fineresolution. Alternatively, fewer conductors can be provided and aminimum number of dots such as, for example, a five by seven matrix, canbe utilized for each character.

Other prior art displays have utilized the so-called double hung windowarrangement of stroke areas. However, in displays requiring a very thinstructure, such as a gas panel display, prior art methods of wiring tothe individual stroke areas would be incompatible with the need forsimplicity, transparency and microminiaturization of the metalliz ationsin the display.

SUMMARY OF THE INVENTION In accordance with the present invention, acharacter display may comprise a display panel having a voltageenergizable displaymedium in a plane medially therewithin, first andsecond arrays of conductors in relatively outer planes of said panelembracing said medium, and circuits connected individually to saidarrays to provide matrix initiation, maintenance and extinction ofoperative voltage stresses within the medium at configured areas ofcongruence between conductors of the first array with conductors of thesecond array. Moreover, the first array may comprise a plurality ofconductor groups, each group corresponding to a column of characterpositions in said display, and the second array may comprise a pluralityof conductor groups, each group corresponding to a row of characterpositions individually corresponding with character positions of saidcolumns of character positions, the conductors of the first group andthe second group at said character positions being configured to havelinear areas of congruence with each other in said character positions,the areas of linear congruence constituting character stroke positionsindividually selectable by matrix energization of a correspondingconductor in each of the first and second groups. v

Accordingly, it is a principle object of the present invention toprovide an improved display having well defined characters with minimummatrix addressing lines and logic.

Another object of the invention is to provide a display as aforesaid inwhich problems of fabrication and construction are minimized.

Yet another object of the invention is to provide a display asaforesaid'wherein matrix conductors are provided with configured and/orsalient conductor elements such that, although the separate conductorsin one plane do not intersect or cross each other, they nevertheless canproduce substantially intersecting or interleaved display lines.

Still another object of the invention is to provide a matrix displayhaving complex land geometries in character positions which provideareas of matrix congruence yielding linear character font elements,without the necessity of cross-overs in either conductor array of thematrix.

The foregoing and other objects, features and advantages of the presentinvention will be apparent from the following description of a preferredembodiment of the invention as illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagramatic representationof a gaseous discharge display having a character matrix panel inaccordance with the invention.

FIGS. 2 and 3 show conductor patterns for the X and Y lines,respectively, within a character position of FIG. 1.

FIG. 4 shows a superposition of the patterns of FIGS. 2 and 3.

FIG. 5 is a diagram showing the approximate areas of congruence of thesuperposed patterns of FIG. 4.

FIG. 6 is a diagramatic showing of signal wave forms employed in theoperation of the display of FIG. 1.

FIG. 7 is a diagramatic cross-section of the display panel of FIG. 1taken about along a line corresponding to the position 7--7 shown inFIG. 4.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring now to the drawings andmore particularly to FIG. 1 thereof, there is illustrated a gaspanelindicated at 20 having a plurality of character positions 22.

In the illustrated embodiment the character positions are arranged in agrid having columns I, ll m, I through 1,1: m,n, and rows 1,1 1,1:through m,l-m,n. The character positions in each row are connected by aplurality of X lines 24 26, 28 to X Selection, Drive and Sustaincircuits 30. The character positions of each column are connected by Ylines 32, 3 3, 36, 38, d0, M to Y Selection, Drive and Sustain circuits44. The gas panel 20 includes an illuminable gas such as a mixture ofneon and argon within a sealed envelope, the vertical and horizontalconductor array being positioned in orthogonal relationship on oppositesides of the envelope. Gas cells within the envelope are selectivelyignited or tired during a write operation by applying to the associatedpair of conductorscoincident signals having a magnitude sufficient tocause the gas voltage to exceed the breakdown voltage. In the preferredembodiment the control potentials for write, read and erase operationsare rectangular AC signals of the type described in copendingapplication Ser. No. 885,086 for Improved Method and Apparatus for a GasDisplay Panel filed by Tony N. Criscimagna et al. Dec. 15, 1969, andassigned to the assignee of the present application. In a gas paneldisplay of this kind, areas of illumination or potential illumination,referred to as cells, are formed by the areas of congruence (i.e.,coincident points) of opposing X and Y conductors on opposite sides ofthe envelope.

In accordance with the present invention the X and Y conductors are soconfigured as to provide areas of congruence corresponding to linearfont elements or character strokes, whereby a character with gooddefinition can be formed with a minimum number of participating X and Yconductors. FIGS. 2 and 3 show configuration of the X and Y conductorsin the region of any of the character positions 22 of FIG. 1. Therelationship of the patterns to any such area 22 is shown by the phantomoutline in FIGS. 2-5. For example, the character position shown may becharacter position 2,2 of FIG. 1, in which case the X drive lines shownwill be group 26 and the Y drive lines shown will be group 34.

Referring more particularly to FIGS. 2 and 3, line XI of group 26 is athrough line having portions 50 and 52 extending to adjacent characterpositions in the same row and eventually to the X selection driveandsustain circuits 30. Similarly, Lines X2-X4 and Yl-Y4 extend throughthe matrix to circuits 30 and 44, respectively. Within the characterposition 22 line X1 is configured to have portions 54, 56, 57 and 58, involtage communication with through connections 50, 52 and comprisinglands located for registration with companion lands in conductors Y1,Y2, Y3 and Y4 of FIG. 3 to define four corresponding cells orluminations sites in the gas panel. In like manner each of the X linesof FIG. 2 has segments for registration with segments of Y lines in FIG.3. For example, line X3 of FIG. 2 has segments 66, 68, 69 and 70positioned for registration with lines 72, 74, 75 and 76, respectively,of lines Y1, Y2, Y3 and Y4 of FIG. 3. It should be noted that linesegment 78 does not register with any line segment in FIG. 3 and isprovided only for communication within line X3 and not as a gas cell orillumination site defining land in the display.

In like manner, line X2 of FIG. 2 has segments 80, 82, 84, 86 whichregister with segments 88, 90, 92, 94 of line Y1, Y2, Y3 and Y4 of FIG.3, and line X4 of FIG. 2 has segments 96, 98, 100, 102 which registerwith segments 104, 106, 108, 110 of lines Y1, Y2, Y3 and Y4 of FIG. 3.

FIG. 4 shows the operative superposition of the patterns of FIGS. 2 and3. The individual shading patterns of FIGS. 2 and 3 are carried intoFIG. 4 so that the double shaded areas show the approximate areas ofcongruence. These areas are repeated in FIG. 5 in somewhat idealizedform as areas A through M which correspond to the segments of FIGS. 2and 3 as follows.

TABLE 1 X, Y SEGMENTS, Figs. 2, 3

ILLUMINATION SITE OR CELL, FIG. 5

7 96, 104 9a, 106 100, 10s 102, no

TABLE 2 X] A B C D X2 E F G H X3 I J K L X4 M N O P Y1 Y2 Y3 Y4 In otherwords, to illuminate segment A of character position 2,2, lines X1 andY1 ofline groups 26 and 34, respectively, are employed. To illuminatesegment B of that character position, lines X1 and Y2 of those linegroups are employed, and so on. The lumination of segments B, C, G and Jwill form a seven," for example. In like manner, an extensive set ofalphabetic, numeric, and arbitrary characters or symbols can be created.

Energization of the various X and Y lines to achieve a display of anumber of such characters is achieved by operation of X Selection Driveand Sustain circuits 30 and Y Selection Drive and Sustain circuits 44.Circuits 30 and 44 may be of any suitable kind appropriate to operationof the display. The details of such circuits and their operation do not,per se, form a part of the present invention. Rather, the presentinvention provides an improvement in the electrode configuration of thedisplay, and the consequent reduction of the number of X, Y lines in amatrix for providing a display of a given resolution. The operation ofone suitable X, Y matrix energization scheme is illustrated in summaryform in the diagrams of FIG. 6.

Diagram A of FIG. 6 illustrates the net voltage difference across eachof the cells or illumination sites during sustain operation. For asustain operation a first square wavetrain is applied to all Xconductors, and a second square wave train, displaced from the firstsquare wave train, is applied to all of the Y conductors. The result isa suare wave train potential difference of Diagram A across all gascells equal to or greater than the sustain level.

For a write operation, the signal shown in Diagram B is applied to theselected cell. To accomplish this, the frequency of the first and secondsquare wavetrains is reduced, and a pulse is superimposed on the firstand second square wave trains as follows: the resultant signal on theselected X conductor has an increased magnitude of one polarity; theresultant signal on the selected Y conductor has an increased magnitudeof the opposite polarity; the resultant signals on the nonselected Xconductors have a decreased magnitude; and theresultant signals on thenon-selected Y conductors have a decreased magnitude whereby theresulting potential difference across the selected cell, and only theselected cell, exceeds the ignition potential of the gas. All of theremaining gas cells receive a sustain signal level. The sustainoperation takes place with the leading edge of the potential differencewave train, and the write operation takes place at the trailing edgeportion of this wave train whereby spill" over to adjacent cells isminimized. The reduction in frequency during a write operation furtherseparates these two events.

Diagram C shows the waveforms applied in sequence to a cell selected forerasure. For an erase operation the first and second square wave trainsare latched down, and a pulse is superimposed on the Y and X conductorsas follows: the resultant signal on the selected X conductor isdecreased; the resultant signal on the selected Y conductor is increasedwhereby the potential difference across the selected cell is reducedbelow the sustain level; the resultant signal on the non-selected Xconductors is increased; whereas the signals on the non-selected Yconductors is decreased. A potential difference, less than the sustainlevel, is applied across the selected gas cell, and this pulse has apolarity opposite to the polarity of the last sustain pulse whereby thegas in the selected cell is driven toward a state of lower molecularactivity, and after a suitable delay, as indicated by the break in thediagram, sustain operations are reinitiated.

Further details of a gas panel display system of this kind shown anddescribed in an article entitled Addi-- tive Pulses Turn On DisplayCells Reliably by Tony N. Criscimagna published in Electro-OpticalSystern Design, Vol. 3, No.9, Aug. 1971, pages 32-37, and

in U. S. Pat. application Ser. No. 885,086 filed Dec. 15, 1969, andassigned to the assignee of this application.

Gas panel operating arrangements of the above referenced kind rely onelectric field and wall charge localization to define the boundaries ofcells, or illumination sites in the gas. Referring to FIG. 7, thispermits the panel 22 to be of open internal construction, that is,without physical barriers between the cells. Thus the panel constructionmay comprise a dielectric envelope having walls 120, 122 and containingan ionizable illuminable gas 124, such as a mixture of neon and argon ornitrogen..Conductors embrace the dielectric envelope 120, 122 onopposite sides of, but separated by the dielectric from, the layer ofgas 124. As shown, these conductors may be in the configuration shown inFIGS. 2, 3 and 4. The panel is completed by outer glass layers 126, 128,providing structural support for X, Y conductors and dielectric, andsuitable connections from the X, Y conductors andcircuits 30 and 44.

If, on a particular half-cycle of the alternating'potential connected toa pair of the conductors, for example conductors X3 and Y3, the gasvoltage exceeds a breakdown voltage, the gas becomes conductive throughthe voltage-induced production of electrons and gas ions, and theselected cell is said to have broken down. In this conductive state,electrons in the gas migrate to the wall which is temporarily positive,and the ions to the wall which is temporarily negative. The chargedparticles collected on the dielectric walls, or wall charge, produce apotential between the dielectric surface and the conductors whichopposes the externally applied potential, and thus reduces the gasvoltage. As current continues to flow through the gas, the opposing wallcharge increases until the gas voltage drops below that necessary tomaintain the gas in a conductive state, and the current discharge isextinguished.

On the next half-cycle of the alternating external potential having apolarity opposite that of the preceding half-cycle, the voltage producedby the wall charge initially adds to that produced externally, so thatthe gas voltage is augmented. Thus the breakdown voltage of the gas isobtained at a lower value of external potential, a current discharge ofopposite sense to the initial discharge is initiated, and a wall chargeof opposite sign to the initial wall charge is established of sufficientmagnitude to cause the discharge to be extinguished.

Thus, after initial breakdown, the wall charge condition may bemaintained in the selected cell by application of a lower potentialdesigned the sustain signal which, combined with the wall charge, causesthe selected cells to be reignited and extinguished continuously at arelatively high frequency to maintain a continuous display. In theillustrated case, the breakdown is between elements 69 and 65, and theilluminated cell is defined by the area of congruency of those elements.Light output for display-purposes is produced in that current.

Alternatively, a gas panel structure having an apertured spacer layerbetween the dielectric layers and operative to isolate the cells fromeach other physically may be utilized. An aperturedconstruction, and ageneral energizing scheme therefor, have been described, for example, inU. S. Pat. No. 3,559,190 to Bitzer.

In either case, the display system of the present invention providesselection of character elements with a maximum of addressing efficiency.In the illustrated embodiment, each character position has sixteenelements individually addressable by selective use of four X throughconductors and four Y through conductors, and the character positionsare individually addressable by selective use of the X and Y conductorgroups.

While the invention has been particularly shown and described withreference to a preferred embodiment thereof, it 'will be understood bythose skilled in the art that other changes in form and details may bemade therein without departing from the spirit and scope of theinvention.

What is claimed is:

1. In a character display comprising a display panel having a voltageenergizable display medium in a plane medially therewithin,

first and second arrays of conductors in relatively outer planes of saidpanel embracing said medium, means connected individually to said arraysto provide matrix initiation, maintenance and extinction of operativevoltage stresses within said medium at areas of congruence betweenconductors of said first array with conductors of said second array, theimprovement comprising said first array comprising a plurality ofmultiple conductor groups, each group corresponding to a column ofcharacter positions in said display,

said second array comprising a plurality of multiple conductor groups,each group corresponding to a row of character positions individuallycongruent with character positions with said columns of characterpositions,

each of the conductors of said first group and said second group at saidcharacter positions being configured to have linear congruence with eachconductor of the other group in said character positions,

the areas of linear congruence constituting character stroke positionsindividually selectable by matrix energization of a correspondingconductor in each of said first and second groups.

2. Apparatus in accordance with claim 1 wherein said conductors areformed with land areas in said character positions providing areas oflinear congruence of character font element configuration.

3. Apparatus in accordance with claim 1 wherein said lines of said firstarray pass through said character positions in electrically parallel andnon-intersecting relationship, and

wherein said lines of said second array pass through said characterpositions in electrically parallel and non-intersecting relationship,

whereby no line crossovers are required within either array.

4. Apparatus in accordance with claim 2 wherein said lines of said firstarray pass through said character positions in electrically parallel andnon-intersecting relationship, and,

wherein said lines of said second array pass through said characterpositions in electrically paralleland non-intersecting relationship,

at least some of said land areas of at least one array including salientportions extending laterally of the corresponding conductor intocongruence with land areas of the opposite array.

5. Apparatus in accordance with claim 1 wherein said display has aself-latching characteristic, whereby the lines of said arrays can beoperated to address said character font elements selectively bycoordinate conductors in said groups in a character position, with thecharacter positions being addressed selectively by coordinate conductorgroups,

so that an array of characters can be presented by said display in aflicker free manner.

6. Apparatus in accordance with claim 1, wherein said display is a gaspanel display and said medium is luminescent gas insulated from saidconductors by dielectric envelope means.

7. Apparatus in accordance with claim 6 wherein said conductors areformed with land areas in said character positions providing areas oflinear congruence of character font element configuration.

8. Apparatus in accordance with claim 7 wherein said lines of said firstarray pass through said character positions in electrically parallel andnon-intersecting relationship, and

wherein said lines of said second array pass through said characterpositions in electrically parallel and non-intersecting relationship,

whereby no line crossovers are required within either array.

9. Apparatus in accordance with claim 8 wherein said lines of said firstarray pass through said character positions in a first single plane, and

wherein said lines of said second array pass through said characterpositions in a second single plane parallel to and spaced from saidfirst plane,

at least some of said land areas of at least one array including salientportions in the corresponding plane extending laterally of thecorresponding conductors into congruence with land areas of the oppositearray,

whereby each character position can have individually selectablecharacter font elements of up to the product of the number of lines inthe corresponding line group of said first array multiplied by thenumber of lines in the corresponding line group of said second array.

10. Apparatus in accordance with claim 9 wherein said dielectriccomprises wall charge storage means operative to maintain self latchingluminescent operation at said areas of congruence.

11. Apparatus in accordance with claim 10 wherein said envelope providesan open layer for said gas with said first plane on one side of saidlayer and said second plane on the other side of said layer,

and said cells are defined entirely by said land areas,

whereby a matrix display panel having a multiplicity of characterpositions each capable of having a multiplicity of individuallyaddressable character font elements is provided in a simple structure.

1. In a character display comprising a display panel having a voltageenergizable display medium in a plane medially therewithin, first andsecond arrays of conductors in relatively outer planes of said panelembracing said medium, means connected individually to said arrays toprovide matrix initiation, maintenance and extinction of operativevoltage stresses within said medium at areas of congruence betweenconductors of said first array with conductors of said second array, theimprovement comprising said first array comprising a plurality ofmultiple conductor groUps, each group corresponding to a column ofcharacter positions in said display, said second array comprising aplurality of multiple conductor groups, each group corresponding to arow of character positions individually congruent with characterpositions with said columns of character positions, each of theconductors of said first group and said second group at said characterpositions being configured to have linear congruence with each conductorof the other group in said character positions, the areas of linearcongruence constituting character stroke positions individuallyselectable by matrix energization of a corresponding conductor in eachof said first and second groups.
 2. Apparatus in accordance with claim 1wherein said conductors are formed with land areas in said characterpositions providing areas of linear congruence of character font elementconfiguration.
 3. Apparatus in accordance with claim 1 wherein saidlines of said first array pass through said character positions inelectrically parallel and non-intersecting relationship, and whereinsaid lines of said second array pass through said character positions inelectrically parallel and non-intersecting relationship, whereby no linecrossovers are required within either array.
 4. Apparatus in accordancewith claim 2 wherein said lines of said first array pass through saidcharacter positions in electrically parallel and non-intersectingrelationship, and, wherein said lines of said second array pass throughsaid character positions in electrically parallel and non-intersectingrelationship, at least some of said land areas of at least one arrayincluding salient portions extending laterally of the correspondingconductor into congruence with land areas of the opposite array. 5.Apparatus in accordance with claim 1 wherein said display has aself-latching characteristic, whereby the lines of said arrays can beoperated to address said character font elements selectively bycoordinate conductors in said groups in a character position, with thecharacter positions being addressed selectively by coordinate conductorgroups, so that an array of characters can be presented by said displayin a flicker free manner.
 6. Apparatus in accordance with claim 1,wherein said display is a gas panel display and said medium isluminescent gas insulated from said conductors by dielectric envelopemeans.
 7. Apparatus in accordance with claim 6 wherein said conductorsare formed with land areas in said character positions providing areasof linear congruence of character font element configuration. 8.Apparatus in accordance with claim 7 wherein said lines of said firstarray pass through said character positions in electrically parallel andnon-intersecting relationship, and wherein said lines of said secondarray pass through said character positions in electrically parallel andnon-intersecting relationship, whereby no line crossovers are requiredwithin either array.
 9. Apparatus in accordance with claim 8 whereinsaid lines of said first array pass through said character positions ina first single plane, and wherein said lines of said second array passthrough said character positions in a second single plane parallel toand spaced from said first plane, at least some of said land areas of atleast one array including salient portions in the corresponding planeextending laterally of the corresponding conductors into congruence withland areas of the opposite array, whereby each character position canhave individually selectable character font elements of up to theproduct of the number of lines in the corresponding line group of saidfirst array multiplied by the number of lines in the corresponding linegroup of said second array.
 10. Apparatus in accordance with claim 9wherein said dielectric comprises wall charge storage means operative tomaintain self latching luminescent operation at said areas ofcongruence.
 11. APparatus in accordance with claim 10 wherein saidenvelope provides an open layer for said gas with said first plane onone side of said layer and said second plane on the other side of saidlayer, and said cells are defined entirely by said land areas, whereby amatrix display panel having a multiplicity of character positions eachcapable of having a multiplicity of individually addressable characterfont elements is provided in a simple structure.